Photoacoustic imaging assessment of acute kidney injury associated with experimental necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is a devastating gastrointestinal condition increasingly recognized to cause systemic complications, including acute kidney injury (AKI). However, the underlying mechanisms and variations in renal impairment remain largely unknown, and there is a lack of non-invasive imaging methods for detecting early kidney injury.

We evaluated kidney injury through a multimodal approach, using a neonatal rat model of experimental NEC. Plasma and renal tissue were analyzed for pro-inflammatory cytokines (TNF-α, IL-6, IL-1β) by ELISA. Histological analysis and immunofluorescence staining were used to identify renal abnormalities and expression of KIM-1 and NGAL. Photoacoustic imaging (PAI) was used to assess renal oxygenation and total hemoglobin as functional biomarkers of kidney injury.

NEC pups showed significant elevations of systemic and renal cytokines, as well as increased expression of KIM-1 and NGAL in proximal tubules of the kidney. Histological examination further confirms the renal injury in the NEC pup kidneys. PAI demonstrated reduction in renal oxygen saturation, offering non-invasive physiological biomarker assessment of kidney damage.

This study introduces PAI as a promising imaging modality for non-invasive evaluation of renal injury in NEC and characterizes AKI associated with NEC as an inflammatory and hypoxic response in the neonatal rat NEC model.